Reversible myocardial failure in a cat with primary hypoparathyroidism.

A 4-year-old domestic shorthair cat presented with tetany. Laboratory testing confirmed severe hypocalcemia and primary hypoparathyroidism. The cat subsequently developed congestive heart failure secondary to myocardial failure and was treated with pimobendan, enalapril, furosemide, calcitriol and calcium salts. All clinical signs resolved and cardiac function returned to normal within 1 month, and remained normal after cessation of all medications except calcitriol. Hypocalcemia-associated cardiomyopathy is a rare, reversible condition that has not previously been reported in a veterinary patient, and it should be considered as a differential diagnosis in patients with myocardial failure.